Bentonite, to seal, needs to be tilled into the soil to a minimum 12" depth, then be properly compacted with a Vibratory sheepsfoot roller at a vibration frequncy that will compact one foot, or more, deep, A standard pull=type sheepsfoot roller can be used, if pulled over 2, 6" lifts. Spreading a layer of plain bentonite over the surface, will not seal at all.
